Besides serving as the main set for the hit PBS series that recently premiered its third season, this imposing landmark and the land it occupies has been home to generations of the Earls of Carnarvon since 1679.

"It's an amazing place to wake up in. I've never lost my sense of wonder for it," said Lady Fiona, the current Countess of Carnarvon, who lives at Highclere with her husband, the Eighth Earl of Carnarvon. She has written a book about the castle, which occupies a lofty hilltop in southern England and welcomes a limited number of visitors each year.

At the forefront of British high society for much of its history, the castle has sheltered some of Britain's most privileged celebrities (including a future king) and has its own hints of intrigue, a World War I period of public service, a stunning link with ancient Egypt and the shadow of a pharaoh's curse. At times, threads of it even have been woven into "Downton Abbey."

Watching all three seasons of "Downton" surely will stoke PBS fans' desire to visit the castle. Happily, they can tour the grounds where Robert, Lord Grantham, walks his Labrador retriever; enjoy the gardens where Violet, the Dowager Countess, sometimes takes tea; and see the castle's main rooms where the lives of the Crawley family and their servants unfold.

But the castle opens only for 70 days a year, and its tour tickets are as hot as the PBS "Masterpiece" series.

In case you can't visit, or to develop an appreciation for the castle's own history before you go, read Lady Fiona's book, "Lady Almina and the Real Downton Abbey, The Lost Legacy of Highclere Castle" (Broadway Paperbacks, $15.99).

Visits to Highclere Park, in Newbury, England, are 10:30 a.m.-1 p.m. (morning tickets) or 1-3:30 p.m. (afternoon tickets) Sundays through Thursdays, July 14 through Sept. 12. Summer tickets go on sale in February and will sell out quickly. For additional opening dates (various holidays during the year), check the website: highclerecastle.co.uk (phone is 011-44-1635-253204). Tickets vary according to currency fluctuations, but they are about $30, adults; $26 seniors and students; and $18 for children. Family admission (for two adults and two or three children) is $82. This includes tour of the castle, its Egyptian Exhibition, gardens and grounds.

Visit the castle by car or take a train from London's Paddington Station to Newbury's Rail Station. Taxis from Newbury should be pre-booked.